13666779025 has 27 divisors (see below), whose sum is σ = 17188654971. Its totient is φ = 10779576240.

The previous prime is 13666779019. The next prime is 13666779029. The reversal of 13666779025 is 52097766631.

It is a happy number.

The square root of 13666779025 is 116905.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 4920040449 + 8746738576 = 70143^2 + 93524^2 .

It is not a de Polignac number, because 13666779025 - 2³ = 13666779017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13666779029) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 60205962 + ... + 60206188.

Almost surely, 2^13666779025 is an apocalyptic number.

13666779025 is the 116905-th square number.

13666779025 is the 58453-rd centered octagonal number.

It is an amenable number.

13666779025 is a deficient number, since it is larger than the sum of its proper divisors (3521875946).

13666779025 is an frugal number, since it uses more digits than its factorization.

13666779025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 670 (or 335 counting only the distinct ones).

The product of its (nonzero) digits is 2857680, while the sum is 52.

The spelling of 13666779025 in words is "thirteen billion, six hundred sixty-six million, seven hundred seventy-nine thousand, twenty-five".